The disclosed embodiments of the present invention relate to processing a differential input, and more particularly, to an amplifier for processing a differential input using amplifier circuits with different driving capabilities and/or different frequency compensation characteristics.
Generally speaking, a differential amplifier is devised to process a differential input. Taking an audio playback application for example, a current steering digital-to-analog converter (DAC) may be employed due to its low power consumption, and an output of the current steering DAC may be fed into a transimpedance amplifier implemented using a fully-differential amplifier due to the fact that the use of the fully-differential amplifier can effectively reduce the output impedance requirement of the current steering DAC. However, it is possible that the audio playback application is required to drive a single-ended load such as a headphone speaker. If one output node of the differential output port of the fully-differential amplifier is simply coupled to the single-ended load for driving the single-ended load, the mismatched loop gain responses for the positive input signal and the negative input signal of the differential input may cause significant output distortion, leading to degradation of the audio playback quality.